The present invention is drawn to a cooling-air outlet for a vehicle, comprising a grill and a frame which encloses said grill and is provided on an outside wall of the vehicle. Said vehicle may be constituted, in particular, by military vehicles and other vehicles which come under fire. It is therefore also the case that the grill is usually a ballistic grill.
A cooling-air outlet of this type is known, for example, from U.S. Pat. No. 4,926,921. In armored vehicles, such an outlet is arranged on the tail, on the top side of the hull or on the side, but preferably on the top side. In non-armored vehicles, it is usually arranged on the front. The cooling air flowing out through it heats up the grill to a temperature of 100.degree. C. and above.
Modern battleground reconnaissance and target acquisition is carried out predominantly with the aid of very sensitive thermal-imaging equipment which supplies black and white video images. This equipment reacts to differences in surface temperature of solid bodies. In other words, the warmer a surface, the lighter it appears on the video image. This enables such so-called hot spots to be detected even at large distances. A grill heated to 100.degree. C. constitutes such a hot spot.
It is the principle object of the invention to provide a grill vent which is, as far as possible, invisible, and thus as difficult to locate as possible, in a thermal-imaging environment.